3D Bioprinter Can Print Multiple Materials Rapidly

Researchers have combined two types of 3D-printing methods to develop a new technique to build therapeutic biomaterials from multiple materials. The research out of the UCLA Samueli School of Engineering paves the way for on-demand printing of complex artificial tissues for use in transplants and other surgeries, researchers said.

The team, led by Ali Khademhosseini, an engineering professor at the university, combined the concepts of stereolithography, which dates back to the 1990s, and digital photo-mask patterning, which dates back to the 2010s, he said.

Researchers at UCLA have developed a multimaterial 3D-printing process for biomaterials. The process combines two types of printing methods to rapidly print numerous hydrogel-based biomaterials at the same time. (Image source: UCLA Samueli School of Engineering)

Researchers developed an optical 3D printer with “one micro-fluidic chip to have multi-material printing,” he told Design News. “The chip allowed the passage of four different photo-crosslinkable inks while providing a cell-friendly environment,” Khademhosseini said. “The set-up provided rapid fabrication of multi-material constructs from cell-laden inks.”

In this way, researchers have demonstrated the first technique to use multiple materials for automated stereolithographic bioprinting—an advance over conventional stereolithographic bioprinting, which only uses one type of material. While the process Khademhosseini described uses four types of bio-inks, researchers said the process could use as many inks as needed for an application.

This multimaterial aspect of the process isn’t its only benefit, Khademhosseini said. Stereolithography-based 3D printing has higher printing resolution and a higher fabrication rate than common types of 3D-printing techniques, so the system also provides a rapid fabrication rate at a high resolution, or 50 microns, he said.

The UCLA team designed its system for small constructs and organoid systems, making it a good option for research-oriented tissue models, Khademhosseini said. The specific materials that the team used in its study are called cell-laden hydrogels that can be photo-crosslinked, which means that they are solidified when exposed to light.

Researchers first used the process to make simple shapes, such as pyramids. Later, they printed complex 3D structures that mimicked parts of muscle tissue and muscle-skeleton connective tissues, as well as shapes mimicking tumors with networks of blood vessels. These latter constructs could be used as biological models to study cancers, according to researchers.

The team tested the physical viability of their biomaterial structures by implanting them in rats and found that their bodies did not reject the printed objects, researchers added. For academic and translational research, scientists can use the system to fabricate organoids and organ-on-chip models in their work, Khademhosseini told Design News. “Such chips can be used to make drug-screening chips and disease models,” he said. Another application of the system could be to optimize ink systems for stereolithography 3D printing.

The researchers plan to continue their work to make it better suited to fabricate larger constructs and even more complex tissue systems, he said. The team published a paper on the work in the journal Advanced Materials, with Amir Miri—a postdoctoral scholar at Harvard Medical School at the time of the study—as first author. Miri is now a researcher at Rowan University.

Elizabeth Montalbano is a freelance writer who has written about technology and culture for 20 years. She has lived and worked as a professional journalist in Phoenix, San Francisco, and New York City. In her free time, she enjoys surfing, traveling, music, yoga, and cooking. She currently resides in a village on the southwest coast of Portugal.

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